The use of an enzyme for hydrolyzing fats and oils has been increased in many cases of the production of hydrolysates of fats and oils (mono-, di-, or triglyceride), or the production of esters from fatty acids and alcohols by the reverse reaction of hydrolysis, and the production of new glycerides by exchanging acyl group of the fats and oils. Especially in the case of producing fats and oils with functionality, a lipase having a position specificity has been used frequently. And, in order to recover and reuse the lipase enzyme, an immobilized enzyme can be used.
Many of the immobilized enzymes which are available at present are offered in a dried form, taking into consideration the inhibition of an enzyme from deactivation during storage and proper handling. However, deactivation of an immobilized enzyme is liable to occur at a step where the immobilized enzyme is dried under reduced pressure, in a vacuum or by heating, and the maximum activity of the immobilized enzyme is not achieved in many cases. Meanwhile, a method of water removal by treating the enzyme with organic solvent has been known (JP-A-2000-253874), but all the same, the maximum activity of the enzyme is not achieved against the original activity of the adsorbed enzyme.
On the other hand, a method for increasing the recovery of enzyme activity has been proposed, wherein the drying of the immobilized enzyme is carried out by contacting with fatty acid derivatives (JP-A-1987-134090). In addition, a method for producing an immobilized enzyme for esterification reaction showing high activity has been published (JP-A-2000-166552, JP-A-2004-81200), wherein the deactivation of the enzyme is prevented by controlling the moisture content of the immobilized enzyme by bringing the immobilized enzyme into contact with a fatty acid glyceride, or dehydrating after bringing the immobilized enzyme into contact with the above glyceride.